The influence of intense ion beams on gas target densities

Görres, J.; Kettner, K. U.; Kräwinkel, H.; Rolfs, C.

doi:10.1016/0029-554x(80)90036-1

Cited by 74 publications

(58 citation statements)

References 6 publications

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“…10) clearly confirm the linear behaviour expected from previous work using other target gases and beams [34][35][36]. The target density can therefore be described by the following relation:…”

Section: Study Of the Beam Heating Effectsupporting

confidence: 86%

“…This effect has been studied in detail previously in static gas targets of 14 N gas, using the resonance scan method [34,35], and of 3 He gas, using double elastic scattering [36]. In the present work, again the resonance scan method is used.…”

Section: Study Of the Beam Heating Effectmentioning

confidence: 76%

“…The beam heating parameter α = (0.44 ± 0.05) × 10 −3 determined here for proton beam in neon gas has to be compared to α = 0.5×10 −3 for proton beam in nitrogen gas [34,35], and (0.91 ± 0.19) × 10 −3 for 4 He + beam in helium gas [36], from former studies. The differences may be explained by the different heat transport coefficients in different gases.…”

Section: Study Of the Beam Heating Effectmentioning

confidence: 91%

“…It is known from previous work [34][35][36] that the beam heating effect is proportional to the power dissipated by the beam inside the gas per unit length, which, in turn, is given by:…”

Section: Study Of the Beam Heating Effectmentioning

confidence: 99%

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A new study of the 22Ne(p, γ)23Na reaction deep underground: Feasibility, setup and first observation of the 186 keV resonance

et al. 2014

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Section: Study Of the Beam Heating Effectsupporting

confidence: 86%

Section: Study Of the Beam Heating Effectmentioning

confidence: 76%

Section: Study Of the Beam Heating Effectmentioning

confidence: 91%

“…It is known from previous work [34][35][36] that the beam heating effect is proportional to the power dissipated by the beam inside the gas per unit length, which, in turn, is given by:…”

Section: Study Of the Beam Heating Effectmentioning

confidence: 99%

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A new study of the 22Ne(p, γ)23Na reaction deep underground: Feasibility, setup and first observation of the 186 keV resonance

et al. 2014

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“…The effective target thickness depends on the pressure (monitored during the irradiations with two capacitance manometers, Fig. 1 m-n), the pressure and temperature profile (measured without ion beam, resulting density uncertainty 0.6 %), the thinning of the target gas through the beam heating effect [39] and the fraction of gases other than 3 He. In order to study the latter two effects, a 100 µm thick silicon detector (Fig.…”

Section: Thementioning

confidence: 99%

Activation Measurement of theHe3(α,γ)Be7Cross Section at Low Energy

Bemmerer¹,

Confortola²,

Costantini³

et al. 2006

Phys. Rev. Lett.

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149

208

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The nuclear physics input from the 3 He(α, γ) 7 Be cross section is a major uncertainty in the fluxes of 7 Be and 8 B neutrinos from the Sun predicted by solar models and in the 7 Li abundance obtained in big-bang nucleosynthesis calculations. The present work reports on a new precision experiment using the activation technique at energies directly relevant to big-bang nucleosynthesis. Previously such low energies had been reached experimentally only by the prompt-γ technique and with inferior precision. Using a windowless gas target, high beam intensity and low background γ-counting facilities, the 3 He(α, γ) 7 Be cross section has been determined at 127, 148 and 169 keV center-of-mass energy with a total uncertainty of 4 %. The sources of systematic uncertainty are discussed in detail. The present data can be used in big-bang nucleosynthesis calculations and to constrain the extrapolation of the 3 He(α, γ) 7 Be astrophysical S-factor to solar energies. The 3 He(α, γ) 7 Be reaction is a critical link in the 7 Be and 8 B branches of the proton-proton (p-p) chain of solar hydrogen burning [1]. At low energies its cross section σ(E) (E denotes the center of mass energy, E α the 4 He beam energy in the laboratory system) can be parameterized by the astrophysical S-factor S(E) defined as. The 9.4 % uncertainty [3] in the Sfactor extrapolation to the solar Gamow energy (23 keV) contributes 8 % to the uncertainty in the predicted fluxes of solar neutrinos from the decays of 7 Be and 8 B [4]. The interior of the Sun, in turn, can be studied [4,5] by comparing this prediction with the data from neutrino detectors [6,7], which determine the 8 B neutrino flux with a total uncertainty as low as 3.5 % [7].Furthermore, the production of 7 Li in big-bang nucleosynthesis (BBN) is highly sensitive to the 3 He(α, γ) 7 Be cross section in the energy range E ≈ 160-380 keV [8], with an adopted uncertainty of 8 % [9]. Based on the baryon-to-photon ratio from observed anisotropies in the cosmic microwave background [10], network calculations predict primordial 7 Li abundances [11] that are significantly higher than observations [12,13]. A lower 3 He(α,γ)7 Be cross section at relevant energies may explain part of this discrepancy. The3 He(α,γ) 7 Be (Q-value: 1.586 MeV) reaction leads to the emission of prompt γ-rays, and the final 7 Be nucleus decays with a half-life of 53.22 ± 0.06 days, emitting a 478 keV γ-ray in 10.44 ± 0.04 % of the cases [14]. The cross section can be measured by detecting either the induced 7 Be activity (activation method) or the prompt γ-rays from the reaction (prompt-γ method). Previous activation studies [15,16,17,18] cover the energy range E = 420-2000 keV. Prompt γ-ray measurements [15,19,20,21,22,23,24] cover E = 107-2500 keV, although with limited precision at low energies.The global shape of the S-factor curve is well reproduced by theoretical calculations [25,26]. However, the slope has been questioned [26] for E ≤ 300 keV, where there are no high-precision data. Furthermore, a global analysis [3] ind...

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CNO hydrogen burning studied deep underground

Bemmerer¹,

Confortola²,

Lemut³

et al.

The 2nd International Conference on Nuclear Physics in Astrophysics

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Abstract. In stars, four hydrogen nuclei are converted into a helium nucleus in two competing nuclear fusion processes, namely the proton-proton chain (p-p chain) and the carbon-nitrogen-oxygen (CNO) cycle. For temperatures above 20 million kelvin, the CNO cycle dominates energy production, and its rate is determined by the slowest process, the 14 N(p, γ) 15 O radiative capture reaction. This reaction proceeds through direct and resonant capture into the ground state and several excited states in 15 O. High energy data for capture into each of these states can be extrapolated to stellar energies using an R-matrix fit. The results from several recent extrapolation studies are discussed. A new experiment at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in Italy's Gran Sasso laboratory measures the total cross section of the 14 N(p, γ) 15 O reaction with a windowless gas target and a 4π BGO summing detector, down to center of mass energies as low as 70 keV. After reviewing the characteristics of the LUNA facility, the main features of this experiment are discussed, as well as astrophysical scenarios where cross section data in the energy range covered have a direct impact, without any extrapolation. PACS

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The influence of intense ion beams on gas target densities

Cited by 74 publications

References 6 publications

A new study of the 22Ne(p, γ)23Na reaction deep underground: Feasibility, setup and first observation of the 186 keV resonance

A new study of the 22Ne(p, γ)23Na reaction deep underground: Feasibility, setup and first observation of the 186 keV resonance

Activation Measurement of theHe3(α,γ)Be7Cross Section at Low Energy

CNO hydrogen burning studied deep underground

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